A high-order signal transmission method and system based on a dual-channel architecture

Abstract

The application discloses a high-order signal transmission method and system based on a double-channel architecture, and belongs to the technical field of communication. The method comprises the following steps: generating four-dimensional chaotic sequences X, Y, Z and V by using a key initial value; performing XOR operation on original data by using X and Y in the four-dimensional chaotic sequences to obtain exclusive or data; performing serial-parallel conversion, QAM mapping and null subcarrier mapping on the exclusive or data to obtain a constellation diagram; performing subcarrier column permutation on the constellation diagram by using Z and V in the four-dimensional chaotic sequences to obtain OFDM encrypted data; respectively performing DSM modulation on the OFDM encrypted data and the key initial value to obtain a baseband information stream and a baseband key stream; driving an optical I / Q modulator to load the baseband information stream and the baseband key stream into orthogonal components of an optical carrier respectively to synthesize a QPSK optical modulation signal; and performing coherent transmission on the QPSK optical modulation signal. The application can reduce the risk of information leakage.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of communication, in particular to a high-order signal transmission method and system based on a dual-channel architecture. BACKGROUND

[0002] At present, the traditional digital mobile front haul (MFH) architecture generally adopts common public radio interface (CPRI), but the frequency spectrum efficiency of CPRI is low, so it has become a bottleneck of MFH. In this case, a MFH architecture based on delta-sigma (DSM) modulation is proposed, which is widely studied due to its high frequency spectrum efficiency and noise robustness. Among them, as a comprehensive solution, this modulation technology can efficiently convert complex analog signals into simple digital pulse sequences, and by integrating oversampling technology and noise shaping strategy, it can significantly improve the in-band signal-to-noise ratio (SNR) of the transmission signal, thereby providing strong support for the generation of high-order quadrature amplitude modulation (QAM) millimeter wave signals, especially for those transmission systems with extremely strict tolerance requirements.

[0003] At the same time, due to the openness of the network, security issues cannot be ignored. Due to the high-order communication system of DSM modulation, its highly structured noise shaping characteristics are easy to be attacked by reverse engineering, and the predictability of modulation parameters and quantization errors leads to the risk of information leakage, and the accuracy of the key transmission process cannot be guaranteed, and the error problem caused by the random generation of the key cannot be avoided. SUMMARY

[0004] The purpose of the present application is to overcome the deficiencies in the prior art, and to provide a high-order signal transmission method and system based on a dual-channel architecture, which can effectively enhance the security of the communication system and reduce the risk of information leakage while ensuring the efficiency of signal transmission.

[0005] To achieve the above purpose, the present application adopts the following technical solutions:

[0006] On the one hand, the present application provides a high-order signal transmission method based on a dual-channel architecture, comprising:

[0007] obtaining original data to be transmitted and a key initial value;

[0008] generating four-dimensional chaotic sequences X, Y, Z, and V through a four-dimensional chaotic system by using the key initial value;

[0009] XOR operation is performed on the original data by using X and Y in the four-dimensional chaotic sequence, to obtain XOR data;

[0010] Serial-parallel conversion, QAM mapping and null subcarrier mapping are performed on the XOR data, to obtain a constellation diagram;

[0011] Column permutation sequence is generated by using Z and V in the four-dimensional chaotic sequence, and subcarrier column permutation is performed on the constellation diagram by using the column permutation sequence, to obtain OFDM encrypted data;

[0012] DSM modulation is performed on the OFDM encrypted data, to obtain a baseband information stream, and DSM modulation is performed on the key initial value, to obtain a baseband key stream;

[0013] The baseband information stream and the baseband key stream are loaded into the quadrature components of an optical carrier by driving an optical I / Q modulator through an arbitrary waveform generator, to synthesize a QPSK optical modulation signal;

[0014] The QPSK optical modulation signal is transmitted to a transmission link for coherent transmission.

[0015] Optionally, the four-dimensional chaotic system is represented as:

[0016] ;

[0017] wherein X, Y, Z and V represent the four-dimensional chaotic sequence; 、 、 、 denote the derivatives of X, Y, Z and V with respect to time t; a, b, c and d represent the parameters of the four-dimensional chaotic system.

[0018] Optionally, XOR operation is performed on the original data by using X and Y in the four-dimensional chaotic sequence, to obtain XOR data, including:

[0019] ;

[0020] ;

[0021] wherein, denotes the XOR data; denotes the original data; denotes the processed four-dimensional chaotic sequence; denotes the XOR operator; X and Y represent the four-dimensional chaotic sequence; denotes the absolute value function; denotes rounding towards zero to the nearest integer; denotes the remainder function.

[0022] Optionally, the OFDM encrypted data is represented as:

[0023] ;

[0024] wherein, represents the OFDM encrypted data at the t th time; , respectively represent the real part and the imaginary part of the signal on the i th subcarrier; represents the frequency of the i th subcarrier; represents the number of subcarriers; represents the imaginary unit; represents the column permutation matrix.

[0025] Optionally, the OFDM encrypted data is subjected to DSM modulation to obtain a baseband information stream, including:

[0026] generating a subcarrier energy distribution of the OFDM encrypted data according to the column permutation order;

[0027] performing nonlinear compression on the OFDM encrypted data exceeding a preset subcarrier energy, and performing gain enhancement on the OFDM encrypted data not exceeding the preset subcarrier energy, to obtain pre-compressed data;

[0028] performing 1-bit noise quantization on the real part data signal in the pre-compressed data to obtain data quantization noise;

[0029] performing real-time spectrum analysis on the data quantization noise according to a dynamic oversampling rate to obtain data oversampling noise;

[0030] inputting the data oversampling noise into a third-order adaptive DSM modulator, and performing noise shaping on the data oversampling noise by using an integrator and a negative feedback loop in the third-order adaptive DSM modulator to obtain data shaping noise;

[0031] transferring the data shaping noise to a spectrum guard interval of the OFDM encrypted data to obtain a baseband information stream;

[0032] wherein, the coefficients of the integrator in the third-order adaptive DSM modulator are optimized in real time by a neural network model, and the parameters of the neural network model are adjusted in real time by a subcarrier signal-to-noise ratio;

[0033] the negative feedback loop in the third-order adaptive DSM modulator includes a subcarrier inter-channel interference compensation factor.

[0034] Optionally, the dynamic oversampling rate is dynamically configured according to a high-frequency component proportion;

[0035] if the high-frequency component proportion exceeds a preset proportion, the dynamic oversampling rate is configured as a first oversampling multiple;

[0036] If the proportion of the high frequency component does not exceed the preset proportion, the dynamic oversampling rate is configured as a second oversampling multiple.

[0037] Optionally, the key initial value is subjected to DSM modulation to obtain a baseband key stream, comprising:

[0038] The key initial value is subjected to 1bit noise quantization to obtain key quantization noise;

[0039] Based on the Logistic mapping initialized by the key hash value, a pseudo-random sequence of the key quantization noise is generated;

[0040] The pseudo-random sequence of the key quantization noise is subjected to XOR processing to obtain XOR key noise;

[0041] According to a preset oversampling rate, the XOR key noise is subjected to real-time spectrum analysis to obtain key oversampling noise;

[0042] The key oversampling noise is input into an independent second-order DSM modulator, and the integrator and negative feedback loop in the independent second-order DSM modulator are used to perform noise shaping on the key oversampling noise to obtain key shaping noise;

[0043] The key shaping noise is shifted to the spectrum protection interval of the key initial value to obtain a baseband key stream;

[0044] The negative feedback loop in the independent second-order DSM modulator comprises a key integrity check factor.

[0045] Optionally, the coefficients of the integrator in the independent second-order DSM modulator and the coefficients of the integrator in the third-order adaptive DSM modulator are orthogonal noise spectrum distribution.

[0046] Optionally, further comprising:

[0047] According to the synchronization code in the baseband key stream, the baseband information stream and the baseband key stream are clock-locked to control the timing deviation of the baseband information stream and the baseband key stream within a preset symbol period.

[0048] On the other hand, the application provides a high-order signal transmission system based on a double-channel architecture, comprising:

[0049] A data acquisition module is configured to acquire original data to be transmitted and a key initial value;

[0050] A chaotic sequence generation module is configured to generate four-dimensional chaotic sequences X, Y, Z and V through a four-dimensional chaotic system by using the key initial value;

[0051] The data encryption module is used for performing XOR operation on the original data by using X and Y in the four-dimensional chaotic sequence to obtain XOR data.

[0052] The constellation mapping module is used for performing serial-parallel conversion, QAM mapping and null subcarrier mapping on the XOR data to obtain a constellation.

[0053] The data secondary encryption module is used for generating column permutation sequence by using Z and V in the four-dimensional chaotic sequence, and performing subcarrier column permutation on the constellation by using the column permutation sequence to obtain OFDM encrypted data.

[0054] The DSM modulation module is used for performing DSM modulation on the OFDM encrypted data to obtain a baseband information stream, and performing DSM modulation on the key initial value to obtain a baseband key stream.

[0055] The signal synthesis module is used for loading the baseband information stream and the baseband key stream into orthogonal components of an optical carrier respectively by driving an optical I / Q modulator through an arbitrary waveform generator to synthesize a QPSK optical modulation signal.

[0056] The signal transmission module is used for transmitting the QPSK optical modulation signal to a transmission link for coherent transmission.

[0057] Compared with the prior art, the present application has the following beneficial effects:

[0058] The present application effectively reduces the noise and interference that the information stream and the key stream may encounter in the transmission process through the double-channel information and key co-transmission based on DSM modulation, and significantly improves the quality and security of signal transmission, thereby greatly improving the spectral characteristics of the entire communication system, enhancing the performance of the high-order communication system of DSM modulation, and transmitting the information stream and the key stream through the I path and the Q path of the optical I / Q modulator respectively without chaotic transmission. The use of coherent transmission realizes the secure reconstruction of the DSM modulation shaping function, the key random mechanism realizes seamless key management through dynamic update of the key stream, eliminates the communication interruption and reconnection overhead in the traditional key distribution process, and brings higher communication efficiency, thereby providing a safe and efficient transmission solution for high-spectrum utilization communication scenarios. BRIEF DESCRIPTION OF DRAWINGS

[0059] Figure 1 Fig. 1 shows a flowchart of the high-order signal transmission method based on the double-channel architecture in an embodiment of the present application;

[0060] Figure 2 Fig. 2 shows a flowchart of the high-order signal transmission method based on the double-channel architecture in another embodiment of the present application;

[0061] Figure 3The figure shows a phase diagram of the four-dimensional chaotic system of the application in an embodiment.

[0062] Figure 4 The figure shows a schematic diagram of the principle of the XOR encryption of the application in an embodiment.

[0063] Figure 5 The figure shows a schematic diagram of the principle of the subcarrier column permutation of the application in an embodiment.

[0064] Figure 6 The figure shows a schematic diagram of the signal processing flow of the application in an embodiment.

[0065] Figure 7 The figure shows a schematic diagram of the flow of the DSM modulation of the application in an embodiment. DETAILED DESCRIPTION

[0066] The technical solutions of the application will be described in detail below with reference to the drawings and specific embodiments. It should be understood that the embodiments of the application and the specific features in the embodiments are detailed descriptions of the technical solutions of the application, and are not limitations of the technical solutions of the application. In the case of no conflict, the technical features in the embodiments of the application and the embodiments can be combined with each other.

[0067] The term "and / or", only describes the association relationship of the associated objects, which means that there can be three relationships, for example, A and / or B, which can represent the three cases of A alone, A and B together, and B alone. In addition, the character " / ", generally represents that the associated objects before and after are in an "or" relationship.

[0068] Embodiment 1

[0069] As Figure 1 shown, the embodiment introduces a high-order signal transmission method based on a double-channel architecture, which is the processing flow of the sending end, and specifically includes the following steps:

[0070] Step one: obtain the original data to be transmitted and the key initial value, specifically:

[0071] The key initial value is a randomly generated key. The key initial value is used to generate four-dimensional chaotic sequences X, Y, Z, and V through a four-dimensional chaotic system;

[0072] The four-dimensional chaotic system is represented as:

[0073] ;

[0074] Wherein, X, Y, Z, and V represent four-dimensional chaotic sequences; 、 、 、 represent the derivatives of X, Y, Z, and V with respect to time t, ; a, b, c, d represent four-dimensional chaotic system parameters. When the four-dimensional chaotic system parameters are set as a = 10, b = 8 / 3, c = 28, and d = -1, the four-dimensional chaotic system is in a chaotic state, in other words, under the condition of a proper initial state S0 = (X0, Y0, Z0, V0), the generated output sequence, i.e., the four-dimensional chaotic sequence, is a random non-periodic sequence.

[0075] For the initial state S0 = (0, 10, 20, 50), the phase diagram of the four-dimensional chaotic system is as shown in Figure 3 The dynamic characteristics show that the system is in a highly complex and irregular chaotic state, which provides reliable security performance for chaotic encryption, wherein the number at each position is mapped to a binary symbol with a length of 4, and the front end is used as a symbol bit to distinguish the positive and negative, 0 represents positive, 1 represents negative, and the middle part is inserted with a binary symbol with a length of 4 as a symbol bit of a decimal point.

[0076] The embodiment includes two-step encryption operations, i.e., an exclusive OR (XOR) operation and subcarrier scrambling. Among them, the four-dimensional chaotic sequences X and Y correspond to Key1, and the four-dimensional chaotic sequences Z and V correspond to Key2, and the two encryption operations are implemented in OFDM modulation.

[0077] The original data is subjected to an XOR operation using the X and Y in the four-dimensional chaotic sequence, to obtain XOR data;

[0078] The original binary data is subjected to an XOR operation, as shown in Figure 4 To obtain the encrypted sequence after the XOR operation, the sequence H = [X, Y] is further processed as:

[0079] ;

[0080] Then, the original data S is encrypted by the XOR operation as:

[0081] ;

[0082] wherein, represents the XOR data; represents the original data; represents the processed four-dimensional chaotic sequence; represents an XOR operator; represents an absolute value function; represents rounding to the nearest integer towards zero; represents a remainder function.

[0083] Step two: serial-parallel conversion, high-order modulation (Quadrature Amplitude Modulation, QAM) mapping, and null subcarrier mapping, specifically:

[0084] The XOR data is subjected to serial-parallel conversion, QAM mapping, and null subcarrier mapping to obtain a constellation diagram, as described in the prior art.

[0085] Step three: subcarrier scrambling, specifically:

[0086] The Z and V in the four-dimensional chaotic sequence are used to generate a column permutation order, and the column permutation order is used to perform column permutation on the subcarriers of the constellation diagram to obtain Orthogonal Frequency Division Multiplexing (OFDM) encrypted data.

[0087] The column permutation matrix is used to realize frequency domain encryption of the subcarrier signals, and the columns in the data table, matrix, or array of the constellation diagram are rearranged to improve the security of the data, as shown in Figure 5

[0088] First, the Z and V in the four-dimensional chaotic sequence are quantized to generate a column permutation order, which determines the position of each column in the OFDM encrypted data.

[0089] Next, the constellation diagram is split into several columns, and the generated column permutation order is used to rearrange each column of the constellation diagram.

[0090] The column permutation process can be regarded as a matrix Therefore, the final OFDM encrypted data is represented as:

[0091] ;

[0092] wherein, represents the OFDM encrypted data at the t-th moment; , represents the real part and the imaginary part of the signal on the i-th subcarrier, respectively; represents the frequency of the i-th subcarrier; represents the number of subcarriers; represents the imaginary unit; represents the column permutation matrix, which is generated by a chaotic system and controls the rearrangement order of the subcarrier columns, i.e., the column permutation order.

[0093] In this embodiment, as shown in Figure 5 ​As shown, the B(1) column in the constellation diagram is unchanged, the B(2) column is exchanged with the A(3) column, the B(k) column is exchanged with the A(m) column, the A(1) column is exchanged with the exchanged B(k) column, the A(2) column is exchanged with a column, and so on, to obtain the OFDM encrypted data.

[0094] Step four: inverse Fourier transform, parallel-serial conversion, and optical power amplification, specifically:

[0095] The OFDM encrypted data is subjected to inverse Fourier transform, parallel-serial conversion, and optical power amplification to obtain amplified data, which is described in detail in the prior art.

[0096] Step five: DSM modulation, specifically:

[0097] The OFDM encrypted data is subjected to DSM modulation to obtain a baseband information stream, and the key initial value is subjected to DSM modulation to obtain a baseband key stream.

[0098] This embodiment uses Delta-sigma (DSM) modulation to realize OFDM modulation of high-order OFDM encrypted data and keys for simultaneous coherent transmission, and DSM modulation-based double-channel key co-transmission, forming a DSM-modulated information stream and a key stream. The original data and the key initial value are both generated by software programming on the transmitter side and are information signals and key signals, respectively, and the modulation orders can be the same or different.

[0099] As shown in FIG. 1, Figure 6 At the transmitting end, the original data S is first subjected to XOR encryption, and then subjected to constellation mapping to obtain a constellation diagram. After this basic encryption, OFDM modulation is performed. In the modulation process, the signal is subjected to secondary encryption processing through specially designed frequency domain subcarrier permutation to generate OFDM encrypted data with a double security mechanism. Subsequently, the OFDM encrypted data and the key initial value are subjected to DSM modulation to obtain a baseband information stream and a baseband key stream, respectively.

[0100] As shown in FIG. 2, Figure 7 The acquisition process of the baseband information stream is as follows:

[0101] The subcarrier energy distribution of the OFDM encrypted data is generated according to the column permutation order;

[0102] The OFDM encrypted data exceeding the preset subcarrier energy is subjected to nonlinear compression to retain the relative phase of the constellation points of the OFDM encrypted data, and the OFDM encrypted data not exceeding the preset subcarrier energy is subjected to gain enhancement to obtain pre-compressed data. The preset subcarrier energy is set according to actual conditions. The OFDM encrypted data with high subcarrier energy is subjected to nonlinear compression to retain the relative phase of the constellation points of the OFDM encrypted data, and the OFDM encrypted data with low subcarrier energy is subjected to gain enhancement.

[0103] 1bit noise quantization is performed on the real part of the pre-compressed data to obtain data quantization noise;

[0104] According to the dynamic oversampling rate, real-time spectral analysis is performed on the data quantization noise to obtain data oversampling noise;

[0105] The data oversampling noise is input into the third-order adaptive DSM modulator, and the integrator and negative feedback loop in the third-order adaptive DSM modulator are used to shape the data oversampling noise to obtain data shaping noise;

[0106] The data shaping noise is shifted to the spectrum guard interval of the OFDM encrypted data to obtain a baseband information stream.

[0107] 1bit noise quantization is no longer directly applied to OFDM encrypted data, but first pre-compressed processing is performed on OFDM encrypted data: according to the column permutation order, i.e., the column permutation matrix, the energy distribution characteristics of the subcarriers of the OFDM encrypted data are generated, nonlinear compression is performed on high-energy subcarriers, the relative phase of the constellation point is preserved, and gain enhancement is performed on low-energy subcarriers to avoid quantization truncation, thereby obtaining pre-compressed data.

[0108] Subsequent 1bit noise quantization is only performed on the real part of the pre-compressed data, and the subcarrier phase information at the quantization decision moment is recorded as an auxiliary parameter for subsequent decryption.

[0109] This modification not only retains the low complexity advantage of 1bit noise quantization, but also matches the statistical characteristics of the quantization noise to the pseudo-random distribution of the encrypted subcarriers through pre-compression processing, avoids distortion of the constellation diagram of the original encrypted signal due to excessive quantization, and provides a matching noise model for the noise shaping of the subsequent third-order adaptive DSM modulator. Combined with the "anti-distortion characteristics of encrypted signals", the pseudo-randomness of encrypted data is used to design a "1bit quantization noise and encryption disturbance joint fuzzy mechanism".

[0110] Among them, the coefficients of the integrator in the third-order adaptive DSM modulator are optimized in real time through a neural network model, and the parameters of the neural network model are adjusted in real time through the subcarrier signal-to-noise ratio; the negative feedback loop in the third-order adaptive DSM modulator includes a subcarrier-to-subcarrier interference compensation factor.

[0111] The dynamic oversampling rate is dynamically configured according to the proportion of high-frequency components; if the proportion of high-frequency components exceeds a preset proportion, the dynamic oversampling rate is configured as a first oversampling multiple; if the proportion of high-frequency components does not exceed the preset proportion, the dynamic oversampling rate is configured as a second oversampling multiple.

[0112] In this embodiment, the preset proportion is 25%, the first oversampling multiple is set to 16 times, and the second oversampling multiple is set to 8 times.

[0113] The obtaining process of the baseband key stream is as follows:

[0114] The key initial value is subjected to 1-bit noise quantization to obtain key quantization noise;

[0115] Based on the Logistic mapping initialized by the key hash value, a pseudo-random sequence of the key quantization noise is generated;

[0116] The pseudo-random sequence of the key quantization noise is subjected to XOR processing to obtain XOR key noise;

[0117] According to a preset oversampling rate, the XOR key noise is subjected to real-time spectrum analysis to obtain key oversampling noise;

[0118] The key oversampling noise is input into an independent second-order DSM modulator, and the integrator and negative feedback loop in the independent second-order DSM modulator are used to perform noise shaping on the key oversampling noise to obtain key shaping noise;

[0119] The key shaping noise is shifted to the spectrum protection interval of the key initial value to obtain the baseband key stream.

[0120] The negative feedback loop in the independent second-order DSM modulator includes a key integrity check factor.

[0121] In this embodiment, the coefficients of the integrator in the independent second-order DSM modulator and the coefficients of the integrator in the third-order adaptive DSM modulator are orthogonal noise spectrum distributions, which can disperse noise energy, avoid frequency band superposition, enhance stability, cooperate with adaptive adjustment, and finally improve the signal-to-noise ratio of the modulator within the target signal bandwidth and expand the applicable signal frequency range.

[0122] According to the synchronization code in the baseband key stream, the baseband information stream and the baseband key stream are clock-locked, and the timing deviation of the baseband information stream and the baseband key stream is controlled within a preset symbol period. The baseband information stream and the baseband key stream are clock-locked through the synchronization code in the key stream, and the timing deviation of the two is controlled within 0.5 symbol periods.

[0123] Finally, the information signal and the key signal are converted into 1-bit digital level sequences, forming two independent baseband information streams and baseband key streams.

[0124] Step six: I / Q modulation is performed through an arbitrary waveform generator, specifically:

[0125] The baseband information stream and the baseband key stream are loaded into the quadrature components of the optical carrier by driving the optical I / Q modulator through the arbitrary waveform generator, and a quadrature phase shift keying (QPSK) optical modulation signal is synthesized.

[0126] The two-channel digital baseband signals, the baseband information stream and the baseband key stream, are first input into the arbitrary waveform generator (AWG), and the information signal and the key signal are loaded into the quadrature components of the optical carrier by driving the optical I / Q modulator, and a QPSK optical modulation signal carrying complete encrypted information is synthesized.

[0127] Step seven: transmitting the QPSK optical modulation signal to the transmission link for coherent transmission.

[0128] In the application of the embodiment, the double-channel information and key co-transmission based on DSM modulation effectively reduces the noise and interference that the information stream and the key stream may encounter in the transmission process, and significantly improves the quality and security of signal transmission, thereby greatly improving the spectral characteristics of the entire communication system, enhancing the performance of the high-order communication system of DSM modulation, and transmitting the information stream and the key stream through the I channel and the Q channel of the optical I / Q modulator respectively, without causing chaotic transmission. Coherent transmission is adopted to realize the secure reconstruction of the DSM modulation shaping function.

[0129] Embodiment 2

[0130] The embodiment introduces a high-order signal transmission system based on a double-channel architecture. Corresponding to the sending end, the system comprises:

[0131] The data acquisition module is configured to acquire original data to be transmitted and a key initial value.

[0132] The chaotic sequence generation module is configured to generate four-dimensional chaotic sequences X, Y, Z, and V through a four-dimensional chaotic system based on the key initial value.

[0133] The data encryption module is configured to perform XOR operation on the original data by using X and Y in the four-dimensional chaotic sequence to obtain exclusive or data.

[0134] The constellation map mapping module is configured to perform serial-parallel conversion, QAM mapping, and null subcarrier mapping on the exclusive or data to obtain a constellation map.

[0135] The data secondary encryption module is configured to generate column permutation order by using Z and V in the four-dimensional chaotic sequence, and perform subcarrier column permutation on the constellation map through the column permutation order to obtain OFDM encrypted data.

[0136] a DSM modulation module, configured to perform DSM modulation on the OFDM encrypted data to obtain a baseband information stream, and perform DSM modulation on the key initial value to obtain a baseband key stream;

[0137] a signal synthesis module, configured to load the baseband information stream and the baseband key stream into quadrature components of an optical carrier respectively by driving an optical I / Q modulator through an arbitrary waveform generator, and synthesize a QPSK optical modulation signal;

[0138] a signal transmission module, configured to transmit the QPSK optical modulation signal to a transmission link for coherent transmission.

[0139] The specific function implementation of each module is described in the related content in the method of Embodiment 1, and is not repeated here.

[0140] Embodiment 3

[0141] Based on Embodiment 1, as shown in the following figure, this embodiment introduces a high-order signal transmission method based on a double-channel architecture, which is a processing flow of a receiving end, and specifically includes the following steps: Figure 2

[0142] Step one: receiving a QPSK optical modulation signal transmitted in a transmission link for coherent transmission;

[0143] Step two: I / Q imbalance compensation, dispersion compensation, and blind equalization, specifically including:

[0144] performing I / Q imbalance compensation, dispersion compensation, and blind equalization on the QPSK optical modulation signal to obtain a blind equalization signal;

[0145] The signal after dispersion compensation enters a blind equalization module, which uses a constant modulus blind equalization algorithm (CMA) to realize signal recovery. As a classical blind equalization algorithm, CMA can effectively offset multipath fading and linear distortion caused by the channel by minimizing the modulus difference of the output signal without prior pilot information.

[0146] Step three: frequency offset compensation and carrier phase recovery, specifically including:

[0147] ​After the equalization processing is completed, due to the existence of factors such as carrier frequency offset and phase noise, the recovered signal may still have residual phase rotation and frequency drift problems, for this, further use the fourth power algorithm to compensate for the frequency offset and phase recovery of the signal. The algorithm makes full use of the high-order statistical characteristics, and for modulation formats such as QAM with rotational symmetry, by performing fourth power operation on the signal, each point in the constellation is rotated to the collinear state, and by analyzing the phase information of the fourth power signal, the carrier frequency offset and the corresponding phase error can be accurately estimated, and then the original signal is compensated in the opposite direction. Rotating, realizing the correction of the signal phase and the effective cancellation of the frequency offset.

[0148] Step four: constellation demodulation mapping, specifically:

[0149] After CMA equalization and fourth power frequency offset compensation and phase recovery processing, the signal obtained by the receiving end has a constellation diagram that has basically recovered to the ideal state, that is, the amplitude and phase of each symbol tend to be stable, and the error is significantly reduced. At this time, the signal contains the main data information and key information after DSM modulation;

[0150] The obtained IQ signal has compensated the channel fading, IQ imbalance and other linear distortions to a large extent.

[0151] Step five: DSM demodulation, specifically:

[0152] The recovered IQ signal is separated into I and Q paths respectively, and a specially designed low-pass filter is applied to each path signal. The low-pass filter not only suppresses out-of-band interference, but also ensures that the phase and amplitude characteristics of the filtered signal are consistent with the processing results at the transmitting end, so as to perform DSM modulation.

[0153] For I path signal, the low-pass filtering mainly retains the original signal component after DSM modulation and noise shaping processing; and for Q path signal, the low-pass filtering retains the key signal after DSM modulation and noise shaping processing. The key signal obtained through the Q path can be used to decrypt the I path signal to obtain the original data.

[0154] Step six: obtain the original data and key initial value, specifically:

[0155] The key signal obtained through the Q path is the key initial value;

[0156] The DSM demodulated signal is subjected to serial-parallel conversion and Fourier transform to obtain a first transformed signal;

[0157] The key obtained by DSM demodulation is used to perform subcarrier demapping on the first transformed signal through a four-dimensional chaotic system to obtain a primary decrypted signal;

[0158] The first decrypted signal is subjected to symbol decision and serial-to-parallel conversion to obtain a second converted signal;

[0159] The second converted signal is subjected to secondary decryption by using the demodulated key through a four-dimensional chaotic system, and the original data is obtained.

[0160] Corresponding to the sending end processing process of Embodiment 1, the receiving end adopts a heterodyne coherent detection scheme, and through the beat frequency effect of the local laser and the signal light, linear demodulation of the optical field information is realized, and finally the coherent transmission processing process from the photon domain to the electrical domain is completed.

[0161] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can adopt a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer usable storage media containing computer usable program code (including but not limited to disk storage, CD-ROM, optical storage, etc.).

[0162] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of the flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0163] These computer program instructions can also be stored in a computer readable storage medium that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable storage medium produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocks Figure 1 The functions specified in one or more flows and / or blocks

[0164] These computer program instructions can also be loaded into a computer or other programmable data processing device, so that a series of operation steps are performed on the computer or other programmable device to produce a computer-implemented process, so that the instructions executed on the computer or other programmable device provide a process for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in one or more flows and / or blocksFigure 1 the steps of the functions specified in the one or more blocks.

[0165] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the above-described specific embodiments, and the above-described specific embodiments are merely illustrative, but not restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.

Claims

1. A high-order signal transmission method based on a two-channel architecture, characterized in that, The method comprises the following steps: obtaining original data to be transmitted and a key initial value; generating a four-dimensional chaotic sequence X, Y, Z, V through the key initial value by a four-dimensional chaotic system; performing XOR operation on the original data by using X and Y in the four-dimensional chaotic sequence to obtain XOR data; performing string-parallel conversion, QAM mapping and null subcarrier mapping on the XOR data to obtain a constellation diagram; generating column permutation order by using Z and V in the four-dimensional chaotic sequence, and performing subcarrier column permutation on the constellation diagram by the column permutation order to obtain OFDM encrypted data; performing DSM modulation on the OFDM encrypted data to obtain a baseband information stream, and performing DSM modulation on the key initial value to obtain a baseband key stream; loading the baseband information stream and the baseband key stream into the orthogonal components of an optical carrier respectively by an arbitrary waveform generator to drive an optical I / Q modulator to synthesize a QPSK optical modulation signal; transmitting the QPSK optical modulation signal to a transmission link for coherent transmission; performing DSM modulation on the OFDM encrypted data to obtain a baseband information stream, comprising: generating subcarrier energy distribution of the OFDM encrypted data according to the column permutation order; performing nonlinear compression on the OFDM encrypted data exceeding a preset subcarrier energy, and performing gain enhancement on the OFDM encrypted data not exceeding the preset subcarrier energy to obtain pre-compressed data; performing 1-bit noise quantization on real part data signals in the pre-compressed data to obtain data quantization noise; performing real-time spectrum analysis on the data quantization noise according to a dynamic oversampling rate to obtain data oversampling noise; inputting the data oversampling noise into a third-order adaptive DSM modulator, and performing noise shaping on the data oversampling noise by an integrator and a negative feedback loop in the third-order adaptive DSM modulator to obtain data shaping noise; shifting the data shaping noise to a spectrum guard interval of the OFDM encrypted data to obtain a baseband information stream; performing DSM modulation on the key initial value to obtain a baseband key stream, comprising: performing 1-bit noise quantization on the key initial value to obtain key quantization noise; generating a pseudo-random sequence of the key quantization noise based on a Logistic mapping initialized by a key hash value; performing XOR processing on the pseudo-random sequence of the key quantization noise to obtain XOR key noise; performing real-time spectrum analysis on the XOR key noise according to a preset oversampling rate to obtain key oversampling noise; inputting the key oversampling noise into an independent second-order DSM modulator, and performing noise shaping on the key oversampling noise by an integrator and a negative feedback loop in the independent second-order DSM modulator to obtain key shaping noise; shifting the key shaping noise to a spectrum guard interval of the key initial value to obtain a baseband key stream.

2. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The four-dimensional chaotic system is represented as: ； Wherein, X, Y, Z, V represent four-dimensional chaotic sequences; , , , The derivatives of X, Y, Z, V with respect to time t are represented by a, b, c, d, respectively.

3. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, performing XOR operation on the original data by using X and Y in the four-dimensional chaotic sequence to obtain XOR data, comprising: ； ； wherein, represents exclusive OR data; represents original data; represents a processed four-dimensional chaotic sequence; represents an XOR operator; X, Y represent four-dimensional chaotic sequences; represents an absolute value function; represents rounding to the nearest integer towards zero; represents a remainder function.

4. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The OFDM encrypted data is represented as: ； wherein, denotes the OFDM encrypted data at the t-th time instant; , denote the real and imaginary parts of the signal on the i-th subcarrier, respectively; denotes the frequency of the i-th subcarrier; denotes the number of subcarriers; denotes the imaginary unit; denotes the column permutation matrix.

5. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The coefficients of the integrator in the third-order adaptive DSM modulator are optimized in real time by a neural network model, and the parameters of the neural network model are adjusted in real time by a subcarrier signal-to-noise ratio. The negative feedback loop in the third-order adaptive DSM modulator comprises a subcarrier interference compensation factor.

6. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The dynamic oversampling rate is dynamically configured according to the proportion of high-frequency components. If the proportion of high-frequency components exceeds a preset proportion, the dynamic oversampling rate is configured as a first oversampling multiple. If the proportion of high-frequency components does not exceed a preset proportion, the dynamic oversampling rate is configured as a second oversampling multiple.

7. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The negative feedback loop in the independent second-order DSM modulator comprises a key integrity check factor.

8. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, The coefficients of the integrator in the independent second-order DSM modulator and the coefficients of the integrator in the third-order adaptive DSM modulator are orthogonal noise spectrum distributions.

9. The high order signal transmission method based on the dual-channel architecture according to claim 1, characterized in that, Further comprising: According to the synchronization code in the baseband key stream, the baseband information stream and the baseband key stream are clock-locked, and the timing deviation of the baseband information stream and the baseband key stream is controlled to be within a preset symbol period.

10. A high order signal transmission system based on a two-channel architecture, characterized in that, Comprising: A data acquisition module configured to acquire original data to be transmitted and a key initial value; A chaotic sequence generation module configured to generate four-dimensional chaotic sequences X, Y, Z, and V from the key initial value through a four-dimensional chaotic system; A data encryption module configured to perform XOR operation on the original data using X and Y in the four-dimensional chaotic sequences to obtain exclusive-OR data; A constellation map mapping module configured to perform serial-parallel conversion, QAM mapping, and null subcarrier mapping on the exclusive-OR data to obtain a constellation map; A data secondary encryption module configured to generate column permutation order using Z and V in the four-dimensional chaotic sequences, and perform subcarrier column permutation on the constellation map through the column permutation order to obtain OFDM encrypted data; A DSM modulation module configured to perform DSM modulation on the OFDM encrypted data to obtain a baseband information stream, and perform DSM modulation on the key initial value to obtain a baseband key stream; A signal synthesis module configured to load the baseband information stream and the baseband key stream into the quadrature components of an optical carrier respectively through an arbitrary waveform generator driving an optical I / Q modulator to synthesize a QPSK optical modulation signal; A signal transmission module configured to transmit the QPSK optical modulation signal to a transmission link for coherent transmission; The DSM modulation on the OFDM encrypted data to obtain the baseband information stream comprises: Generating subcarrier energy distribution of the OFDM encrypted data according to the column permutation order; Performing nonlinear compression on the OFDM encrypted data exceeding a preset subcarrier energy and gain boosting on the OFDM encrypted data not exceeding the preset subcarrier energy to obtain pre-compressed data; Performing 1-bit noise quantization on real part data signals in the pre-compressed data to obtain data quantization noise; Performing real-time spectrum analysis on the data quantization noise according to a dynamic oversampling rate to obtain data oversampling noise; Inputting the data oversampling noise into a third-order adaptive DSM modulator, and performing noise shaping on the data oversampling noise using an integrator and a negative feedback loop in the third-order adaptive DSM modulator to obtain data shaping noise; Shifting the data shaping noise to a spectrum protection interval of the OFDM encrypted data to obtain the baseband information stream; The DSM modulation on the key initial value to obtain the baseband key stream comprises: 1bit noise quantization is performed on the key initial value to obtain key quantization noise; a pseudo-random sequence of the key quantization noise is generated based on a Logistic mapping initialized by a key hash value; an exclusive-OR process is performed on the pseudo-random sequence of the key quantization noise to obtain exclusive-OR key noise; real-time spectrum analysis is performed on the exclusive-OR key noise according to a preset oversampling rate to obtain key oversampling noise; the key oversampling noise is input into an independent second-order DSM modulator, and the key oversampling noise is noise-shaped by an integrator and a negative feedback loop in the independent second-order DSM modulator to obtain key shaping noise; the key shaping noise is shifted to a spectrum guard interval of the key initial value to obtain a baseband key stream.

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